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Tsung-Hsun Wu
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Re: QNX disable eide read-ahead
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Tsung-Hsun Wu
10/22/2008 2:32 AM
post15384
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Re: QNX disable eide read-ahead
After second retry, the problem not only happen in QNX 6.3.2 but also 6.3.0
For "devb-eide blk commit=high, alloc=0, cache=0, nora" and use read/write function calls (not fread/fwrite)to disable
read-ahead and write-behind caching. Both QNX 6.3.2 or 6.3.0 + SP3 + 6.3.2a installation, we get same read but
different write benchmark for different IDE flash.
For example, there are two flash IDE disk, one is PIO4 and another is UltraATA2. The writing benckmark is 1.6MB/sec for
PIO4 and 5MB/sec for UltraATA 2. However, the reading speed is both 90MB/sec for both PIO4 and UltraATA2.
It looks like we did not know how to disable read-ahead of devb-eide...
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Tsung-Hsun Wu
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Re: QNX disable eide read-ahead
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Tsung-Hsun Wu
10/22/2008 2:32 AM
post15385
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Re: QNX disable eide read-ahead
After second retry, the problem not only happen in QNX 6.3.2 but also 6.3.0
For "devb-eide blk commit=high, alloc=0, cache=0, nora" and use read/write function calls (not fread/fwrite)to disable
read-ahead and write-behind caching. Both QNX 6.3.2 or 6.3.0 + SP3 + 6.3.2a installation, we get same read but
different write benchmark for different IDE flash.
For example, there are two flash IDE disk, one is PIO4 and another is UltraATA2. The writing benckmark is 1.6MB/sec for
PIO4 and 5MB/sec for UltraATA 2. However, the reading speed is both 90MB/sec for both PIO4 and UltraATA2.
It looks like we did not know how to disable read-ahead of devb-eide...
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Tsung-Hsun Wu
|
Re: QNX disable eide read-ahead
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Tsung-Hsun Wu
10/22/2008 2:32 AM
post15386
|
Re: QNX disable eide read-ahead
After second retry, the problem not only happen in QNX 6.3.2 but also 6.3.0
For "devb-eide blk commit=high, alloc=0, cache=0, nora" and use read/write function calls (not fread/fwrite)to disable
read-ahead and write-behind caching. Both QNX 6.3.2 or 6.3.0 + SP3 + 6.3.2a installation, we get same read but
different write benchmark for different IDE flash.
For example, there are two flash IDE disk, one is PIO4 and another is UltraATA2. The writing benckmark is 1.6MB/sec for
PIO4 and 5MB/sec for UltraATA 2. However, the reading speed is both 90MB/sec for both PIO4 and UltraATA2.
It looks like we did not know how to disable read-ahead of devb-eide...
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